In the manufacture of paper, various fabrics are used to form, dewater, mold, dry, support, and/or transfer the paper web from the headbox to the reel. During the operation of the paper machine, these fabrics often become dirty, contaminated with residual fibers, or contaminated with residual chemicals. As a result, fabric cleaning apparatuses such as flooded nip showers, scarfing showers, high pressure fan jets, needle showers, and the like are used to remove the contaminants. This process can leave the fabric relatively wet after being sprayed by water, which is typically used as the cleaning agent. For applications where the fabric operates in a wet environment, such as the forming section, the retained moisture on the fabric after the cleaning process poses few, if any, issues. However, for fabrics which need to be relatively dry to carry out their intended function, or for fabrics that carry the paper web through the drying section, the retained water can cause operational issues or significantly increase the drying costs required to evaporate the retained moisture on the fabric after the cleaning operation.
Typically, fabrics operating in the dryer section of the paper machine are dewatered after cleaning by the use of a vacuum box, an air knife, or an air shower to blow the excess water from the fabric. Vacuum has the disadvantage of being the most expensive of these options to produce and is limited in differential pressure obtainable by the available atmospheric pressure. The air knife can have several drawbacks when used for dewatering the cleaned fabric. First, compressed air is relatively expensive and the operation of one or more air knives can consume a large amount of energy when used to dewater the fabric. Second, an air knife is only partially effective in removing all of the retained water in the fabric after cleaning. Additionally, air knives and vacuum boxes can create drag on the fabric surface, which increases the fabric's wear rate, thereby reducing the fabric's life.
Therefore, what is needed is a fabric dewatering apparatus and method that consumes less energy. Also, what is needed is a fabric dewatering apparatus and method that removes more retained moisture from the fabric.